Wildlife Habitat Tracking
Automating the Habitat Evaluation Procedure

To assess the effects on wildlife a Habitat Evaluation Procedure (HEP) was conducted on Satsop Forest (then known as the Satsop Nuclear Site) and completed in 1994. This procedure was created by US Fish and Wildlife Service as an accounting system to assess the effects of projects on wildlife habitat. Wildlife habitat is used as "currency" with changes due project activities and/or mitigation are compared. Habitat quality and quantity are estimated using Habitat Suitability Index (HSI) models and Habitat Unit (HU) calculations. The process follows the following steps:

  1. Cover typing
  2. Model selection
  3. Model application
  4. Data collection
  5. Target year selection
  6. Mitigation alternative creation
  7. Impact assessment

The following is a brief over view of the original HEP and the automated HEP. For more in depth information contact Kevin Ceder via e-mail or phone at 206.543.0827.

Original HEP

Cover Typing
Cover types were originally delineated from aerial photographs based on apparent vegetation changes. Maps were created using CAD based on the cover typing. The following cover types were used:
 Conifer  C1 - Early successional  C2 - Pole  C3 - Mature  C3T - C3, thinned  C4 - Late successional  C4T - C4, thinned
Deciduous  H1 - Early successional  H2 - Sapling  H3 - Mature      
 Mixed  M1 - Early successional  M2 - Pole  M3 - Mature      
 Palustrine  PE - Pal. emergent  PS - Pal. shrub PF - Pal. forest      
 Other  G - Grass  B - Brush  BA - Barren  P - Ponds  D - Developed  

All the cover types were defined based on various measures. For definitions click on the cover type. Changes in the cover types was estimated by the team that performed the HEP. Thus a cover type would be "allowed" to develop in a certain trajectory. For each target year these estimates were made and acreages calculated from a map.

Model Selection
Five models were selected to track different habitat types. These were:

  1. Cooper's hawk (Accipiter cooperii) - Mature mixed and deciduous forests
  2. Spotted towhee (Pipilo erythrophtalmus) - Young forests and brushlands
  3. Southern red-backed vole (Clethrionomys gapperi) - Pole/sapling and mature forests
  4. Pileated woodpecker (Dryocopus pileatus) - Pole/sapling, mature and late-successional conifer and mixed forests
  5. Black-tailed deer (Odocoileus hemionus columbianus) - All non-developed habitat types

Model Application
All models used were published between 1978 (spotted towhee) and 1991 (black-tailed deer) and designed for all cover types, with the exception of the spotted towhee model that is designed for deciduous woodlands. The Cooper's hawk model has since been updated but it is being applied as it was in the original HEP. During the original HEP it was decided that the models would be applied to specific cover types to track changes in those cover types. The were applied as follows:

Data Collection
Each species model has different habitat requirements. Thus data collection needed to be done accordingly. The following attributes, which can be broken down into tree-based and non-tree-based attributes, were measured in 1991:

Tree Based

Non-tree-based

These attributes were averaged for each cover type. These values were then used for HSI and HU calculations.

Target Year Selection
The HEP uses target years to estimate the habitat impacts of a project. In essence a few discrete snapshots in time are examined to assess the effect of the project. The years chosen were:

Mitigation Alternative Creation
Five mitigation alternatives were created for the Satsop Nuclear Site:

Impact Assessment
For each target year for each alternative Habitat Suitability Index (HSI) values were calculated for each cover type. These numbers were then used to calculate the number of Habitat Units (HU) for each species at each target year. The HU's were then used to calculate Average Annual Habitat Units (AAHU) for each species for each alternative. The AAHU's under each mitigation alternative were then compared for selection of a preferred alternative.

Automation of the HEP

To help develop more management alternatives for Satsop Forest the HEP process was automated in the Landscape Management System (LMS). This was done by coding the cover typing rules, HSI models, and HU and AAHU calculations into LMS and using an improved timber inventory.  This was done using the following process:

  1. Data collection
  2. Portfolio creation
  3. Cover type coding
  4. Model coding
  5. HSI, HU, and AAHU calculations

Once this was done input data for the HSI models could then be calculated by programs running in LMS.  This was very straight forward for tree-based variables.  Simply a direct calculation.  For non-tree-based variables data from the 1991 HEP data collection that was related to each cover type was used.  The cover type was determined based on the cover type rules and an attribute value assigned to that cover type.  These attribute values were then used to calculate HSI for each species for each stand.  These figures were then used to calculate the HU's for each stand and the landscape for each species as well as the AAHU's for each species for the life of the management alternative.

Data Collection
During the summer of 1998 a timber inventory of Satsop Forest was conducted.  This was necessary to get tree-based data of sufficient quality to create a n LMS portfolio for LMS.  The attributes measured were:

These measurements were done with nested plots.  A variable radius plot using a BAF 20 or BAF 40 prism depending on tree sizes for trees and snags with DBH >5" with a 1/300th acre fixed radius plot from the same plot center for trees and snags with DBH <5" and downed wood.  Height, crown ratio, and breast height age were measured for the largest tree on each plot for site index calculations.  Heights and crown ratios for the remaining trees were estimated using the height dubbing function in the Forest Vegetation Simulator (FVS) growth model.

Portfolio Creation
A portfolio for LMS brings together a variety of landscape data.  These are:

Calculating the stand level acreage, slope, aspect, and elevation required creation of new GIS data for Satsop Forest.  This was done from CAD maps created for the original HEP with calculations made using ArcInfo functions created by Phil Hurvitrz, the GIS guru at the College of Forest Resources, University of Washington.

Cover Type Coding
Creating the cover typing code from the cover type rules uses a system of "if" statements once the values for all necessary attributes for each stand have been calculated by LMS.  Each stand is then assigned a cover type for each period of the management cycle.  When initially running the cover typing rules some issues were noted.  Some stands were falling all the way through the cover typing rules without being assigned a cover type code.  Some minor modifications of the rules were made.  These can be seen on the HEP cover typing page.

Model Coding
HSI model are published in the form of graphs.  Input values are found on the x-axis, a vertical line is drawn to the line or curve on the graph, and a horizontal line is drawn to the y-axis for a HSI value, ranging from 0.0-1.0 for that attribute.  The models used contain three to five attributes.  These are then multiplied and raised to a power, depending on the number of variables, to yield a final HSI ranging from 0.0-1.0.  For more information see: http://www.nwrc.gov/wdb/pub/hsi/hsiindex.html

HSI, HU, and AAHU Calculations
HSI values are calculated for each species using tree-based values calculated directly from current and projected forest inventory by LMS and cover type averages of non-tree-based values related to cover types assigned using current and projected inventory information.  These values are calculated for each species for each stand on the landscape.  The HSI value is then used to calculate HU's by multiplying the HSI by the acres of the stand then summing them for all the stands in the habitat cover types for that species.  AAHU's are calculated by averaging each period's total HU's for each species over the life of the management plan.
 

Updated 20/12/2000 by Kevin "thujaman" Ceder